Estimation of fracture toughness and shear yield stress of orthotropic materials in cutting with rotating tools

The cutting force is an energetic effect of splitting material, and might be considered from a point of view of modern fracture mechanics. Forecasting of the shear plane angle in cutting broaden possibilities for modelling of the cutting process even for thin uncut chips. Such mathematical model has been developed here for description of the orthotropic materials' cutting on the base of fracture theory, and includes work of separation (fracture toughness) in addition to the material plasticity and friction. The original methodology of simultane- ous determination of the fracture toughness and the shear yield strength on the basis of wood cutting forces (or cutting power) is also presented in this paper. The set of data nec- essary for computation can be easily obtained while cutting wood with common rotating tools, such as a circular saw or a router bit. The results generated include both fracture toughness and shear yield stresses in the shear plane, separately for two anatomical direc- tions of wood. The simplicity and reliability of this method provides wide range of practical applications.